A variable star, of early B or late O types, undergoing radial
pulsations with short periods (< 1 day).
Beta Cephei stars are confined within a narrow band of the
→ H-R diagram above the upper
→ main sequence. They are believed to be
near the end of core hydrogen-burning stars of approximately 10 to 20 solar masses.
The famous bright stars → Spica
and → Mirzam belong to this family.

A member of a class of → pulsating stars with
periods less than 0.3 days, → spectral types A or F,
and visual light amplitudes in the range from a few thousands of a
magnitude to about 0.8 mag. On the → H-R diagram,
δ Scuti stars form a group which lies in an
→ instability strip
which includes the classical → Cepheids at its
brightest end and the pulsating → white dwarfs at its
faintest limit. These stars can show very complex light variations since,
while some of them are pulsating in one radial mode only, others may be pulsating
simultaneously in several radial and non-radial modes.

Named after the prototype star δ of constellation → Scutum;
→ variable.

dependent variable

ورتنده‌ی ِ وابسته

vartande-ye vâbasté

Fr.: variable dépendante

Math.: A variable whose value depends on the value assigned to
another value. For example, in the equation y = 2x, the value of y depends
on that of x. See also → independent variable.

Mechanics: One of the variables used to describe a system in
classical mechanics, such as coordinates (of a particle),
components of velocity, momentum, angular momentum, and functions of these quantities.

A theory based on the hypothesis that the discrepancies with respect to classical reality
found in → quantum mechanics stem from our lack of knowledge
about the observed system (→ EPR paradox).
According to this hypothesis, the system should be
described by additional quantum parameters, of still unknown nature,
but different from position, velocity, spin, etc. The hidden variable
theory has been ruled out by the violation of
→ Bell's inequality for all theories
with local property, as suggested by the → Aspect experiment.